Azimuth instrument.



PATENTED MAY 23, 1905. B. H. CAMDEN. AZIMUTH INSTRUMENT. APPLIUATIONFILED JUNE 1, 1904.

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No. 790,674. PATENTED MAY 23, 1905.

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AZIMUTH INSTRUMENT.

APPLICATION FILED JUNE 1, 1904.

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UNITED ST TES Patented May 23, 1905.

PATENT. OFFICE.

AZIMUTH INSTRUMENT.

SPECIFICATION forming part of Letters Patent No. 790,674., dated May 23,1905. Application filed June 1, 1904. Serial No. 210,676.

To all whom, it may concern:

Be it known that I, BERNARD H. CAMDEN, lieutenantUnitedStatesRevenuerCutter Service, stationed at Boston, inthe county ofSuffolk and State of Massachusetts, have invented a certain new anduseful Improvement in Azimuth Instruments, of which the following is afull, clear, and exact description, reference being had to theaccompanying drawings.

My invention relates to azimuth instruments for use with marinecompasses, and has for its object the production of an instrument ofthis type thatwill be simple, durable, and comparatively inexpensive ofconstruction, that may be readily applied to and removed from theordinarycompass, that will accurately record the bearing of the sun orother object which is observed, and that will besusceptible of easyoperation in a rough sea.

The invention may be defined generally as consisting in the combinationsof elements embodied in the claims hereto annexed.

Referringto the drawings, Figure 1 represents a perspective view of amarine compass of ordinary construction having applied thereto myinstrument}; Fig. 2 represents an enlarged perspective View of myinstrument, said view being taken from the side opposite to that fromwhich Fig. l is viewed. Fig. 3 represents a plan view showingmy-instrument applied to a compass, the compass being shown in dottedlines and the vertical member of my instrument being removed. Fig. 4represents a transverse sectional view taken on the line 4 40f Fig. 3,showing my instrument and a portion of the compass to which the same isapplied.

Describing the parts by reference characters, l'represents myinstrument,the same are rounded off, the center of curvature of such rounded endsbeing the center of the compass circle or ring 4:, the plate fittingsnugly within the inner periphery of said 7 is a sight-wire 11.

ring. This insures that when said plate is placed upon the glasscovering 5 the longitu: dinal axis of saidplate will correspond with adiameter'of said ring. A line 7 is formed on said plate, as by scoringthe metal thereof, said line corresponding to .the axis of the plate anda diameter of the ring 4. Adjacent to each end of said plate there is asightopening 8, extending through said plate above the scale on thecompass-card. A wire 9, forming, in effect, an extension of the line 7,spans each of the openings 8. Adjacent to each of the sight-openings 8and preferably between the same and the center of the plate there isprovided a'yoke 10, which may be of inverted-V shape, as shown.Extending perpendicularly from the top of each of said yokes to theplate 2 and intersecting the line By means of the operating handle orlug 12 at each end of the plate the latter may be rotated in order totake the bearing of any object by means of the wires 11. The bearing ofsuch object may then be readily observed by'noting the position of theappropriatewire 9 with respect to the compass-circle therebelow.

In taking an azimuth of the sun or other j heavenly body I employ withthe base member above described a vertical member 3. This verticalmember is provided with a base 13, preferably of circular form,socketing in a corresponding recess 14 in the member 2. When inoperative position, the plane of the vertical member 3 is in the planeof the line 7 of the base member. Extending vertically from a pointabove the center of the base member 2 (and the center of thecompass-circle) is a slot 15, said slot extending nearly to the top ofthe vertical member. To facilitate adjusting the vertical member, aswell as to plane of the vertical member, is secured to the base member2, whereby the compass may be leveled in the direction of said basemember at the time of taking an observation of the sun or other heavenlybody.

The various parts of this instrument are of course made of non-magneticmaterial.

In order to take an azimuth, as of the sun, the base member is rotatedby means of the lugs or handles 12 until the member 3 is substantiallyat right angles to the sun, whereupon a thin ray of light will beprojected through the slit 15 across the upper face of the compass,marking the reverse bearing of the sun. In reading such bearing with myinstrument it is necessary only to keep the base member 2 level, as bydepressing the compass by means of the finger, reading the bearing whilethe instrument is level. Owing to the thinness of the metal of thevertical member,l can provide the same with a sufliciently narrow slotto insure an accurate bearing and at the same time make it unnecessaryto set said vertical member at exactly right angles to the sun. Inpractice the ship may swing through three or four points of the compasswithout cutting off the beam of light passing through said-slit, therebyrendering unnecessary the exercise of any particular care or attentionin steering the vessel. The extreme simplicity of the device, making itnecessary only to level the base member 2 by means of the finger,together with the adaptability of the same to accurate reading, renderssaid device peculiarly adapted for taking an accurate azimuth in arolling sea.

In order to take the bearing of a distant object, the vertical membermay be removed and the base member rotated until the vertical wires 11are brought to bear upon the object. The direct bearing of said objectmay be read through the sight-opening 8 at the end of the base member,which is directed toward said object, while its reverse bearing may beread through the other opening. The employment of the sight-holes withthe wires extending across the same in the axial line of the base memberprovides a simple and accurate device for reading the bearing of theobject on the compass-card below said member.

In order to head the vessel on any desired magnetic bearing, I employboth the vertical and the base member, as follows: By means of thevertical member the magnetic bearing of the sun may be obtained in themanner heretofore indicated. Having observed this bearing, then by meansof the sight-openings in the base member set the instrument at an anglewith the lubbers point on the compass equal to the angle between thedesired ships course and the observed magnetic bearing of the sun. Swingthe ship until the shadow from the vertical wire 11 at the end of theinstrument near the sun falls on the longitudinal line 7. The ship isthen heading on the desired magnetic course. In a similar manner theship can be headed on a magnetic course when the magnetic bearing of adistant object is known. As the vertical member will be in the way ofobserving the shadow cast by the vertical wire at the end of the basemember, said vertical member may be removed before swinging the ship.

From the foregoing description it will be apparent that I have producedan azimuth instrument which is extremely simple and economical inconstruction, which will not readily get out of adjustment, there beingno reflect ing mirrors or prisms employed therewith, which will enablethe operator to take azimuth bearings with great facility and accuracy,which may be easily operated to head the vessel on any desired magneticcourse, and which will by the employment of the slotted vertical memberpermit the employment of the instrument on a cloudy day.

While I have described my invention in detail, it will be obvious thatsuch details may be departed from more or less without departing fromthe spirit of my invention, and I do not propose to be limited to suchdetails except as they may appear in the claims hereto annexed or berendered necessary by the prior art.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

l. The combination of a compass having the usual ring, of an azimuthattachment therefor comprising a longitudinal base member adapted to fitwithin said ring and provided at its opposite ends with means forcentering said member within the ring, a vertical member carried by saidbase member and provided with a vertical slot, a level extendingparallel with the plane of the face of said vertical member, said basemember being rotatable within said compass-ring, substantially asdescribed.

2. An azimuth attachment for compasses comprising a base member adaptedto rest upon the top of a compass and to lit closely withindiametrically opposite points of the compass-ring and having a centralsocket and a traverse slot extending from said socket to one of theedges of said base member which is parallel with the longitudinal axisthereof, a vertical member provided with a base litting in the socket inthe base member, said base being provided with a slot extending beyondits center and constituting a continuation of the slot in the basemember, whereby the vertical member is readily positioned and thereading of a heavenly body near the horizon is facilitated,substantially as described.

3. An azimuth instrument consisting of a member adapted to rest and berotated upon the top of a compass, a sight-vane adjacent to each end ofsaid member, said member being provided with diametrically opposite openings therethrough above the compass-card, and awire in each opening bymeans of which the bearings may be read on the card, substantially' asdescribed.

4. An azimuth instrument consisting of a member adapted to rest upon thetop of a compass within the inner periphery of the ring thereof andextending diametrically across said compass, said member being providednear each end with an opening therethrough above the compass-card, asight-vane carried by said member adjacent to each of said openings andeach provided with a vertical wire, a wire extending across each of saidopenings, all of said wires being in a vertical plane corresponding to adiameter of the compass-card, substantially as described.

5. In combination with a compass, an attachment therefor consisting of amember adapted to rest and be rotated upon the top of said compass, asight-vane adjacent to each end of said member, said member being provided with means located above the compasscard for indicating with saidcard the bearing of an object, substantially as described.

6. An attachment for use with compasses consisting of a base memberadapted to rest and be rotated on a compass, said base member having anaxial line thereon and having adjacent to an end thereof means forindicating with the-compass-card a desired course or bearing, a verticalmember adjacent to said end of the base member and in the vertical planeof the axial line, and a central vertical member having meanscooperating with the compass-card for indicating thereon the bearing ofthe sun or other heavenly body, substantially as described.

7. An attachment for use with compasses consisting of a base memberadapted to rest and be rotated on a compass, said base member having anaxial line thereon correspond ing to a diameter of the compass and asightopening adjacent to an end of the same with a wire extending acrossthe same, a vertical wire adjacent to said opening,both of said wiresand said axial line being in the same served.

sun or other heavenly body, substantially as described.

8. An azimuth attachmentfor compasses comprising a base member adaptedto rest upon the top of a compass and be rotated thereupon, a verticalmember supported by said base member above the center of the coinpass,said vertical member being provided with a slot extending through thebase me mber and said base member being provided with a cut-out portionor recess therein cor responding to and registering with the slot in thevertical member, whereby the bearing of a heavenly body near the horizonmay be 0b- 9. An azimuth attachment for compasses comprising a basemember having near each end thereof a sight-vane, a central verticalmember supported by said base member and having means for indicating thebearing of the sun or other heavenly body, said vertical member beingmovably fitted to said base member, whereby an unobstructed held ofsight between said vane-s may be afforded.

10. An attachment for compasses consisting of a base member adapted tobe rotated above the compass, said base member being provided with aline in the vertical plane of a diameter of the compass andhaving'adjacent to an end thereof means for indicating with I thecompass-card a desired course or bearing, a sight-vane adjacent to saidend of the base member, said vane being in the plane of the line on thebase member, and a central vertical member also in the plane of saidline and having means for indicating the bearing of a heavenly body.

In testimony whereof I aflix my signature in the presence of twowitnesses.

BERNARD H. CAMDEN.

Witnesses:

' S. M. RooK,

H. D. HINOKLEY.

